Spark-plug.



F. H. KROGER.

SPARK GAP. I

APPLICATION FILED JULY 10, 1912.

1,1325589'. Pate nted Mar.23,1915.

7 7 II 0 1- 6 ii k g 4 4? a. 2+ 4 1 in 4 3"" 7 6 1 1' 6 a Q i 4 i i 4 K I 4" i 7 I 1 Q P '7 7 l O WITNESSES: INVENTOR M ma n/ UNITED STATES PAEENT OFFICE.

FRED H. KBOGER, OF BROOKLYN, NEVT YORK. ASEIGNOR, BY IvIESNE ASSIGNMENTS, TO

SAMUEL M. KIN'INER. OF PITTSBURGH, PENNSYLVANIA, AND HALSEY M. BAR- RETT, OF BLOOMFIELD, NEW JERSEY, RECEIVER-S.

SPARK-GAP.

Specification of Letters Patent.

Patented Mar. 23, 1915.

Applicationfiled July 16, 1912. Serial No. 709,663.

T all whom it may cancer-n:

Be it known that I, Faun H. Knoonn, a citizen of the United States, residing at Zrooklvn, New York, have invented a certain no and useful Spark-Gap for Wireless-Telegraphy Apparatus, of which the following is a specification.

My invention relates to apparatus for generating oscillating currents forn'adiatu g electro-magnetic wares and the llkc and 1s here shown as designed for a spark gap in wireless telegraphy apparatus. Its primary objects are to secure an accurate and easlly adjusted series of sparking surfaces and to arrange for the spark freely playing over such surfaces so as to render the spark uniform; to provide a perfectly quiet spark gap; to chcapen and simplify the construction of series spark gaps; to render the number of sparking spaces readily ad ustable, and to generally improve the construction and operation of the spark gap.

In the accompanying drawmg I have shown a simple form of construction embodving my invention, Figure 1 being a plan view of the construction having a serles of eight gaps, and Fig. 2 is a side elevation and vertical central section of one of the spark gap elements of the same.-

It is already known that it 1s advantageous to distribute the spark over a serles of small gaps, and that the sparking conditions are bestin a closed space, from which the oxygen may speedily be exhausted. And it is also known that it is of advantage to arrange the sparking surfaces so that the discharge may freely play overan extended surface. ,It has heretofore been very (lllllcult to attain these ends eiiiciently without great expense and very delicate adjustment. I have discovered great advantages in having the discharge take place between concentric cylinders, while at the same time such construction greatly simplifies the apparatus and renders the exclusion of air easy, as Well as the proper spacing of the parts.

As shown-in the drawings, I have preferably provided an insulating plate 3 upon which are mounted a series of open spring clips 4 connected in pairs by a strip of metal 4 and held on the plate 3 by bolts 5 and screws 5*, and bolts 5 furnishing the terminals'as Well as convenient means for attaching to any convenient support.

The gap itself is formed by two metal cylinders, 6 and 10, properly spaced and held in perfect alinement by grooved blocks 7 of insulating material at each end of cylinders 6. The complete unit is held together and made air tight by soft rubber disks 8 and brass nuts 9 on each 'end of the inner cylinder 10. Thus the spark flows from the in- (lented part of the inner surface of the cylinder 6 to the central siaipporting cylinder 10 and then again from the outer surface of this cylinder back to another sin-rounding cylinder 6. The space between the elements (5 and 10 is by this construction air-tight and.

fixed in volume and the parts are held rigidly and accurately so that there is a very small gap between the cylinders and it is.

uniform around the circumference, and the discharge may thus play over the surface around the concentric cylinders in the closed space, :ultomaticaily adapting itself to the various places of discharge as ten'ip'erature conditions and condition of surface may change. The gap is efliciently cooled by circulation through the tube 10 as well as by free radiation from the cylinder 6.

It will be 'understood that as here shown there is a series of eight gaps and that the number of gaps. may be varied conveniently by removing or inserting different numbers of the separate cylinder elements containing a pair of gaps. It will be observed that the clip P is connected to the clip 4 by a conducting strip 4 and these being staggered in pairs offers a ready means of inserting or taking out any one of the gap elements.

The advantages of my construction flow from its furnishing a pair of concentric cylindrical surfaces very close together and in the same inclosed space, and from the superior cooling, the ease with which accuracy is obtained, the ease of' repair, and the ease of adjustment. Other advantages will readily occur to those familiar with the art.

Having thus described my invention and illustrated its use, what I claim is the following:

1. A plural spark gap comprising a series of pairs of concentric cylinders providing sparking spaces, each cylinder being electrically connected with a like cylinder of another pair.

2. A spark gap comprising a suitable mounting, and a. series of pairs of removable supporting base, a series of staggered pairs of spring clips, a series of spark gap elements su ported in said cli s substantially as described, and each suc element comprising airs of concentric cylinders formlng spar gaps.

5. A spark gap element comprising a central cylinder, an insulating support therefor and a screw nut thereon, a series of insulating washers on the central cylinder and a series of larger cylinders outside the central cylinder and supported on said Washers, and spaced apart, said Washers forming air-tight compartments between the central and the outside cylinders, substantially as described.

6. A spark gap for wireless telegraphy apparatus comprising a series of pairs of alternately large and small cylindrical surfaces concentrically arranged, and means for causing a discharge serially between said cylindrical surfaces, each cylinder being electrically connected with a like cylinder of I another pair.

In testimony whereof I have hereunto signed my name in the presence of the subscribing Witnesses.

} FRED H. KROGER.

Witnesses:

WALTER J JoNEs, JOSEPH H. Es UIRo. 

